


Basic Biology

by Wolf_n_Bones



Category: Undertale
Genre: Classroom Sex, F/M, Teacher/Student, Toys, mastrubation
Language: English
Status: Completed
Published: 2018-12-12
Updated: 2018-12-12
Packaged: 2019-09-17 01:07:48
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,591
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16964847
Author URL: https://archiveofourown.org/users/Wolf_n_Bones/pseuds/Wolf_n_Bones
Summary: Blue failed his biology test. To not get kicked of his course he needs tutoring. Good thing his devilish tutor is there to help~





	Basic Biology

Blue nervously looked at the door leading to his tutoring class. He had heard the rumors of the new tutor. People whispered he was the devil himself, giving him the nickname ‘Mr. Sunshine’. With his sharp fangs and cheekbones and even sharper tongue and gaze. His punishments were harsh and unforgiving, so everyone tried to stay out of tutoring… But poor Blue had majorly screwed up some biology tests, ending up having to take tutoring if he wanted to continue his course.  
It wasn’t like he hadn’t studied, he had!… Unfortunately it were the wrong subjects… Blue had been absent for a few weeks due to illness. He had asked multiple people what the subjects were and everyone told him the same. But once the test was there everyone but him was prepared on the subject. He ended up tacking a note to his test explaining what had happened but it didn’t do him much good… He sighed, taking the knob and slowly turning it with a gulp.

The room looked like any ordinary class room… Desks, chairs, globe, posters of anatomy, cabinet with books and other biology paraphernalia… Teacher’s desk with the devilish tutor seated behind it… The rumors were right. Blue thought looking over the teacher with a blush, getting even more nervous.

‘Don’t linger in the hallway, get in and sit down.’ His sharp voice cut through the silent room, he hadn’t even looked up from his papers. Blue let out a squeak, hurrying into the classroom and closing the door, taking a seat as commanded. Only the sound of shuffling papers was heard for a few moments until Fell spoke up again. ‘You were sent here by mr. B, correct?’ His lights flashed up from the paper he was holding. Blue gulped, sinking into his chair under the intense stare.

‘Y-yes…’ He replied embarrassed. ‘I-I failed my biology test…’ Blue didn’t dare look at the tutor, which in turn annoyed Fell.

‘Look at me when you speak to me.’ He spoke, Blue’s sockets quickly snapping from his desk to face that intense stare. ‘Let’s get to work.’ Fell added. The hour passed quicker than Blue thought, the devilish tutor while strict helped him more than Blue imagined. He actually learned a lot that hour. ‘I’ll see you tomorrow.’ Fell spoke after giving Blue his homework. The days passed and Blue got to know his tutor a bit better. He really wasn’t as bad as the rumors deemed him to be. ‘Today will be your last day with me.’ Fell spoke. Blue nodded, feeling a little sting in his chest. His test would be tomorrow and if he passed he wouldn’t need Fell’s tutoring anymore. If he failed…. Well, he better find a job… Blue bit his mandible. He couldn’t afford to fail this test… ‘Let’s see what stuck with you, shall we?’ Fell spoke opening the book to the page he had given Blue as homework. A blush spread on Blue’s cheeks as he stared at the genitalia on the page. ‘Name every part of the female genitalia.’ He heard his tutor’s calm voice tell him. He gulped, slightly squirming in his seat. Fell picked up on it but didn’t say a thing.

‘V-vulva… Labia majora… Labia minora… C-clitoris… Utheral opening… Uterus… Overies…’ Blue slightly stuttered. He was embarrassed he still had to blush about this stuff. Fell nodded pleased.

‘Good. Now name the male genitalia.’ He demanded, watching Blue squirm a little more in his seat before the little skeleton opened his mouth to answer him.

‘S-scrotum… Testicles… S-shaft… Head… Urethera… P-prostrate…’ Blue spoke, a soft squeak escaping at the end. He glanced up to his tutor only to see a nod of approval.

‘Good, you remember. Let’s continue with the last of the chapter shall we?’ Blue nodded, glad that part had been over and done with. He let out a relieved little sigh, ignoring the dull throb between his legs and the burning question of how his tutor’s thing would look. The rest of the hour was the same as always. Fell explaining and Blue asking questions and taking notes. At the end of the hour he was ready to take his test. ‘You’ve done well, Blue.’ Fell spoke while wiping the chalk of the board. ‘I’m confident you’ll pass your test.’ He placed the wiper back on the little ledge. Blue pulled his back pack on his shoulders ready to go home.

‘It’s all thanks to you, mr. Sunshine.’ Fell grunted, leaning against the board. He looked at the small bright skeleton in front of him. He would miss the little guy… Maybe. He was by far the most willing to learn and… Pleasant to teach…

‘You did most of it yourself. I just guided you.’ Fell spoke, his sockets glanced over to the door. The janitor was already cleaning the hallways. He motioned to the door with his skull. ‘Go on. Go home. It’s getting late.’ He spoke a little softer than usual. Blue smiled softly and turned. He lingered at the door, peering back over his shoulder.

‘I’ll tell you how it went tomorrow.’ He smiled. The corners of Fell’s mouth slightly curved up. He made a small amused huff.

‘Don’t linger in the door, get going.’ He responded, making Blue smile even wider before he ran off. The small skeleton made it home safely, dropping his bag near his desk as he entered his room. He closed the door and flopped on the bed with a sigh. He looked at the clock, Papy wouldn’t be home for at least another hour… Blue lightly rubbed his legs together. The thought of what Fell’s cock would look like back on his mind, rousing the dull throb back from its slumber. Blue’s cheeks heated up once again as he squirmed on his bed. His eyes slowly gliding over to the desk drawer near the head of his bed……. It.. It couldn’t hurt, could it? He blushed, pulling the drawer open and taking out the toy. He looked at the dildo in his hands. Closing his eyes he imagined it to be Fell’s length and gave the head a little lick. Blue let out a soft moan, licking the toy again. He lay back down in the pillows, licking and sucking on the toy. His other hand slowly making its way between his legs. He let out a soft mewl, feeling his boney digits glide over his clothed pelvis. The hot magic sparking into his cock. He lightly squirmed rubbing himself through the fabric and licking the toy. He closed his sockets and imagined his devilish teacher touching him. His long boney digits stroking Blue’s cute little cock as the little skeleton pleasured his hot throbbing cock. ‘Good boy~’ Blue would hear him purr, arousing the skeleton even more. ‘take it aalll in~ You deserve a little treat for being good~’ Blue softly moaned, un-buttoning his shorts and ghosting his phalanges over his hot ecto flesh.

‘Mwaahhh….’ He softly keened, sticking out his tongue and eagerly sucking on the head of the toy. The growly purr of Fell in his mind added to the heat he was feeling. ‘please…’ He softly whimpered to his imaginary tutor. ‘More…’ He drew slow circles over the slit of his cock. The little thing twitched, sending waves of pleasure down his spine. ‘Please fuck me..’ Blue whispered thickly to his fantasy.

‘Suck me off first.’ He imagined Fell growl at him pressing the toy in his mouth as he did. Slowly pushing it in and pulling it out. A few more mewls escaped him. ‘Then I’ll wreck your pelvis with my cock~’ He imagined Fell purr near his skull. Blue moaned, eagerly sucking off the toy and he firmly stroked himself. ‘Fuck you’re good~’ The imaginary Fell growled. ‘Such a good little slut~’ Blue let out a needy whimper, slicking up the toy as well as he could before popping it out of his mouth. He grabbed a pillow, placing the toy in the middle before he straddled the pillow. The little blueberry slowly lowered himself on the toy.

‘Ah-!… Aaaaahhhh~’ He moaned, clasping a hand over his mouth. A few small tears sprung from his sockets as he adjusted to the intrusion. Slowly he rocked his hips back and forth, imagining the dirty talk and firm strokes coming from Fell. He panted as he rode the pillow and dildo. The fabric felt amazing against his heated flesh. ‘Yes… Yes… Mmheehhh.. Yes~!’ He softly chanted, completely in the grip of his own fantasy and ecstasy. With another firm jerk he came, arching his back and magic splattering all over his bed. Blue panted, dazed and hot from pleasure. He faintly heard the front door open.

‘Blue, I’m home!’ He could hear Honey call out to him. The skeleton quickly gathered himself.

‘Welcome home, brother!’ He chimmed, slowly letting the toy slide out and gathering the dirty linen. ‘I’m going to wash up before dinner okay?’ He called out.

‘A’right, I’ll start dinner!’ His brother replied. A sigh of relief escaped Blue as he set off to the bathroom. He had dinner with his brother after he washed up and went to bed, dreaming of Fell’s digits on his bones. It was difficult to concentrate for him at the exam but it didn’t stop him from getting a near perfect score. The little skeleton was so happy and excited he nearly knocked Fell flat against the wall. The tall skeleton grunted falling back against the wall instead.

‘I did it!’ Blue cried out with starry eyes. ‘I passed the test with a near perfect grade!’ Fell looked at the excited skeleton, a small tug on the corners of his fangs curled into a smirk.

‘Near perfect, hhmm~? Congradulations~’ He spoke, glad the little skeleton’s tutoring had paid off. Blue flustered and Fell raised an eyebone, smirk widening. ‘What were you thinking about to get only a near perfect score~?’ He teased. Blue looked away shyly. A nervous chuckle bubbling in his throat.

‘I-I don’t know~… M-maybe I need more tutoring?’ He carefully glanced up at Fell. The devilish tutor picking up on his desire.

‘… Close the door, I’ll give you another private lesson.’ Blue eagerly closed the door, excited for what was to come. He looked back at Fell who had sat down in his chair. His predatory gaze fluttering the heat in Blue’s gut. The tall skeleton pats his lap, motioning the smaller to sit down. Blue did as his tutor commanded. ‘I belief the next chapter is about reproduction.’ He spoke, hot breath tickling Blue’s vertebrae. The berry opened his mouth in a soundless moan, a shudder going down his back.

‘Y-yes…’ He answered softly. Fell ran his fingers up Blue’s sides, causing the smaller to shudder and squirm even more. Rubbing his pelvis against Fell’s. The devilish tutor smirked, softly nipping at the others vertebrae and circling his arms around him. Blue shudders, holding back a mewl as he watched his tutor open the book to the next chapter.

‘Let’s begin from the start then.’ Fell softly growled, his long digits trailing down Blue’s pelvis to the front, already feeling a bulge form. The smaller let out a needy whimper, pressing his erection against the ghosting fingers. Fell slowly rolled his pelvis against the other’s tailbone. ‘First both need to be properly aroused~’ He purred a growl, prying a soft mewl from Blue who nodded and rubbed his tailbone against Fell’s own pooling magic. The tall skeleton dragged his fangs across the exposed bones of the other. Drawing out a low moan as Blue exposed more for the devilish tutor to ravage. With a flick of his wrist he had opened Blue’s shorts, slipping the long digits into the lacy prison to free the captive. Blue bucked into his hand eagerly.

‘Mweehh…’ He softly mewled, needing to feel more of those lanky fingers. ‘Ah..ahnd when.. when aroused?’ He breathed thickly, shuddering as the jolts of pleasure shot through his spine. Fell slowly rubbed his thumb over the small beads of precum, slicking up the head of Blue’s cock and making the other tremble in his lap. He kissed and licked the exposed bone the little one had given him, rolling his hips into the eagerly waiting berry. He unbuckled his own slacks, freeing the bone pressing up against Blue’s tailbone. The little skeleton lightly jolted, feeling the spikes of Fell’s cock rub between his thighs.

‘After both are fully aroused~…’ Fell dragged out, lifting Blue’s pelvis and pressing the head of his throbbing cock against the puckered hole. The other glanced over his shoulder, begging Fell to just enter him. ‘They insert their penis…’ Fell growled near Blue’s skull, slowly entering the petite skeleton, making his breath hitch and body tremble. A shuddery moan passed his teeth as he eagerly pushed back on the intruding phallus. Fell was so much bigger than Blue’s toy… The spikes on the underside stroked and strapped against his sensitive insides prying another moan from the little skeleton. The tall skeleton watched his pupil quiver in his lap as he fully sheathed himself inside. He held back a soft growl as he felt Blue’s welcoming warm hole squeeze on his throbbing dick. ‘… And fuck their mate like this~’ He gently caressed Blue’s hips as he began rolling his pelvis against the other. Ripping a keen from the other who arches his back with a needy whine. Blue leaned back, gripping Fell’s arm to steady himself as the tall devilish tutor rutted into him.

‘Mwweehh~… Y-yes… Yes-!’ The little blue skeleton cried shuddering and moaning. He never thought he’d feel so much pleasure in his life. This was way better than the toy he was using…. He whined, feeling long hard fingers wrap around his neglected cock and firmly stroking to the pace Fell fucked him in. The pleasure set every nerve end in his body on fire, keeping Blue mewling for more. ‘Please-!’ He begged Fell. ‘Mmoore please-!’ He whined. With a growl Fell picked up the little skeleton, throwing him down on the desk and pinning him. His hips roughly slapping against the smaller one, creating a wet, lewd noise and arousing them even more. ‘Aahh-! Yes-!’ Blue panted, moan muffled but the book his skull was pressed into. The scent of their sex making the little skeleton light-headed and ready for release. Fell growled, leaning over and biting on Blue’s shoulder, the smaller letting out a pained yelp before fading back to pleasured moans. ‘C-close!’ He breathed, cock twitching in Fell’s long digits.

‘Cum for me, little rabbit~’ Fell growled. ‘Let me fill you up to the brim~’ Those words pushed Blue over the edge. He arched his back with a soundless cry as his cum painted the floor under the desk. Fell grunted, feeling the tight hole squeeze down on him. He buried himself deep within, releasing the thick load inside of Blue. The small skeleton milking him for every drop he got. The room fell silent except for their joined panting. Fell pulled Blue back against his chest as he sat back down on the chair. There was silence for a few minutes more as they caught their breath.

‘Thanks for the private lesson~’ Blue whispered with a satisfied and cheeky grin. Glancing up at Fell with a devious gleam in his sockets. Fell’s fangs curled in a grin.

‘Same time next week, little rabbit?’ He purred, getting a soft ‘mweh heh’ and nod in return.

**Author's Note:**

> Moved from wolf-n-bones.tumblr due to NSFW ban.


End file.
